src/java.base/share/classes/sun/net/www/protocol/http/AuthenticationInfo.java

*** 51,60 ****
--- 51,61 ----
  //      policy in HttpURLConnection.  A failure on baz.foo.com shouldn't
  //      uncache foo.com!
  
  public abstract class AuthenticationInfo extends AuthCacheValue implements Cloneable {
  
+     @java.io.Serial
      static final long serialVersionUID = -2588378268010453259L;
  
      // Constants saying what kind of authroization this is.  This determines
      // the namespace in the hash table lookup.
      public static final char SERVER_AUTHENTICATION = 's';
*** 496,505 ****
--- 497,507 ----
          }
      }
  
      String s1, s2;  /* used for serialization of pw */
  
+     @java.io.Serial
      private synchronized void readObject(ObjectInputStream s)
          throws IOException, ClassNotFoundException
      {
          s.defaultReadObject ();
          pw = new PasswordAuthentication (s1, s2.toCharArray());
*** 507,516 ****
--- 509,519 ----
          if (authenticatorKey == null) {
              authenticatorKey = AuthenticatorKeys.DEFAULT;
          }
      }
  
+     @java.io.Serial
      private synchronized void writeObject(java.io.ObjectOutputStream s)
          throws IOException
      {
          Objects.requireNonNull(authenticatorKey);
          s1 = pw.getUserName();